In recent years, SSDs (Solid State Drives) have been proposed as data storage apparatuses. The SSD uses a NAND flash memory (hereinafter sometimes simply referred to as a flash memory) that is a rewritable nonvolatile memory. An example of the NAND flash memory is a three-dimensional stack memory (BiCS: Bit Cost Scalable) formed by stacking layers on a semiconductor substrate in a perpendicular direction and processing the layers at a time.